Study On Preparation,Surface Modification And Antitumor Properties Of Gold Nanoflowers

Photothermal therapy is a method that uses heat energy converted by light energy to inhibit the rapid growth of tumors.Gold nanoflower is a photothermal agent with good biocompatibility.In view of the shortcomings of low tumor suppression efficiency of gold nanoparticles,this article improved the anti-tumor effect of gold nanoparticles by studying the morphology,stability and delivery of doxorubicin of gold nanoparticles.Polymyxin E has a unique ring structure,amphiphilic structure and rich functional groups,making it an excellent template for regulating the morphology of gold nanoparticles.In this paper,polymyxin E was used to tune the shape of gold nanoparticles,and then the zwitterionic material with strong hydrophilicity and high biocompatibility was used to improve the stability of the gold nanoflowers.The gold nanoflowers were used to deliver DOX to achieve combined anti-tumor effect of chemotherapy and hyperthermia.The research contents and conclusions of this article are as follows:(1)The amphiphilic polymyxin E was self-assembled to form micelles in aqueous solution,ascorbic acid was used to reduce chloroauric acid and prepared micelles were used to regulate the morphology of gold nanoparticles to successfully prepare polymyxin E-templated gold nanoflowers(PE@AuNFs).Gold nanoflowers with rough surface not only had significant absorption for near infrared light,but also had light-to-heat conversion efficiency of 35.9%.PE@AuNFs almost had no cytotoxicity and exhibited obvious antibacterial properties and cytotoxicity after 808 nm laser irradiation.After 0.257 mM PE@AuNFs were irradiated for 15 min,the cell viability of HeLa cells was 19%.In vivo experiments in mice showed that after a week of drug addition and light treatment,almost no tumor tissue was observed.(2)In order to further improve the long-term stability of existing PE@AuNFs,thiol-functionalized sulfobetaine(SB-SH)was first synthesized,and then SB-SH was modified on the surface of PE@AuNFs through S-Au bonds to obtain SB-SH stabilized PE@AuNFs(SB-SH@AuNFs)in this chapter.Compared with PE@AuNFs,SB-SH@AuNFs did not generate any precipitate within 24 h,and had a higher light-to-heat conversion efficiency of 38.9%.After 0.193 mM SB-SH@AuNFs were irradiated for 10 min,the cell viability of A549 cells was only 11%.In vivo experiments also showed that when the concentration of SB-SH@AuNFs was 50% of that of PE@AuNFs,they achieved the same tumor suppressing effect.(3)In order to further improve the anti-tumor ability of PE@AuNFs,the gold nanoflowers(DOX-SH@AuNFs)with dual effects of chemotherapy and hyperthermia were prepared by modifying the surface of PE@AuNFs using doxorubicin(DOX-SH)through S-Au bond.The experimental results showed that the light-to-heat conversion efficiency of DOX-SH@AuNFs was 33.9%.DOX-SH@AuNFs showed better synergistic anti-tumor ability than PE@AuNFs.After 0.193 mM DOX-SH@AuNFs were irradiated with laser for 10 min,the cell viability of A549 cells was 20%.